Electrical Troubleshooting Quiz — Oct. 6, 2020
Imagine the following scenario: You’re a maintenance electrician for a multi-building plant, and each building has its own crew. You recently transferred to another building on the premises. Several lines in this building have experienced motor-related failures, and your boss thinks it’s a problem with the MCC. He shows you a repair report from the electrician you replaced. He points to one phrase and says it repeatedly: “Found and removed mold at MCC.”
You ask yourself the following questions: Was it black mold or green mold? How much mold was present? From what location was it removed? Was it on the exterior, or was it on energized parts? Was it removed with vinegar or with an antifungal agent that stops regrowth but not the cause?
Your boss wants you to solve the underlying problem if there is one. How might you go about doing this?
First, contact the electrician you replaced and see if he can recall anything helpful. For example, he may say there was black mold on the bottom of a cubicle door, and that he wiped it off with a rag. Ask him if that might have just been ordinary crud rather than black mold.
Conversely, what if he says he found something significant in the MCC, or you are unable to reach him? Get a couple of humidity/temperature transmitting gages and put them inside the MCC and another just outside the MCC as a reference. Check the readings after a few hours.
If you discover it is significantly damper inside the MCC but also cooler, then you need to vent or dehumidify the MCC (contact the manufacturer for recommendations). If it is significantly damper but not cooler, then water may be coming in through a raceway. Identify each raceway with a moisture source on the other end, and seal it there.
About the Author
Mark Lamendola
Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.
Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.
Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.